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The electron cyclotron (EC) heating & current drive (H&CD) system on ITER provides plasma heating by generating, transmitting, and launching high-intensity, high-frequency (170 GHz) electromagnetic wave energy steerable across the plasma cross-section. The transmission line (TL) subsystem connects the Matching Optics Unit (MOU) on each of the 24 gyrotrons to the 32 feed points in the four upper launchers and the 24 feed points in the equatorial launcher. Each TL must be able to operate at up to 1.2 MW of input power for up to 1 hour pulse lengths. The TL system contains 50 mm water-cooled corrugated waveguide, 90o miter bends, 140o miter bends, polarizer miter bend pairs, switches, expansion units, pumpouts, DC breaks, MOU-TL adapters, Radio Frequency (RF) loads, and isolation shutter valves. A detailed finite element analysis has been used to verify the thermo-mechanical performance of each component. The microwave performance has been analyzed using a 2-D electromagnetic code combined with a Monte Carlo code. This approach allows the impact of manufacturing and installation tolerances to be assessed and optimized to provide a high probability of achieving the system performance requirements. Prototypes of the waveguide and TL components have been fabricated and tested at high-power. Production contracts are now being issued for fabrication and delivery of the waveguide and components to ITER.

The ITER Electron Cyclotron Resonance Heating (ECRH) & Current Drive (ECCD) system is planned to be progressively installed and commissioned following the four stage approach of the ITER Research Plan. Starting with an injection of up to 5.8 MW from one Upper Launcher (UL) in the vacuum vessel to assist the plasma breakdown during First Plasma (FP) operation, the system will then be extended to achieve a capability of 20 MW injected power in Pre-Fusion Plasma Operation (PFPO) and Fusion Power Operation (FPO) phases. Development of optical modelling was required to characterize the optical performance of the FP configuration with the so-called First Plasma Protection Components. An optical 3D model using Zemax OpticStudio® has been developed and extended to the UL. Effects of higher order modes, thermal deformations and tolerances on the UL functionality have been characterized and are presented. Finally, in preparation of plasma operation and in the frame of the EC system upgrade layout optimisation, ECRH-ECCD modelling is being undertaken within the ITER Integrated Modelling and Analysis (IMAS) suite.

Time dependent simulations that evolve consistently the magnetic equilibrium and plasma pressure profiles and the width and frequency rotation of magnetic islands under the effect of the Electron Cyclotron feedback system are used to assess whether the control of NTMs on ITER is compatible with other simulataneous functionalities of the EC system, like core heating and current profile tailoring, or sawtooth control. Results indicate that the power needs for control can be reduced if the EC power is reserved and if pre-emptive control is used as opposed to an active search for an already developed island.

The four ITER Electron Cyclotron Upper Launchers (UL) are designed to control Magneto- Hydrodynamic instabilities with the deposition of Electron Cyclotron power. According to the present design, each launcher comprises two rows of four input waveguides, whose output beam is focused and driven towards the plasma by four sets of mirrors. In order to study the beam-launcher interaction throughout quasi-optical propagation, with particular attention to straylight behaviour, and to verify analytical calculations, a 3D model of the UL optical system has been implemented with the electromagnetic code GRASP® and the Physical Optics method. Detailed description of the components are introduced: pure hybrid mode HE11 from cylindrical waveguide as input beams, real shapes of the mirror contours, semi-analytical description of the ellipsoidal surfaces of focussing mirrors. A conceptual calculation scheme has been developed in order to take into account not only the direct contribution of the single source on its next scatterer but also the first order indirect effects: crosstalk from different lines of the same row and crosstalk from different rows have been evaluated after reflection on the first and third set of mirrors. The evaluations presented have been performed on the preliminary UL design, the last major milestone before finalization; however, the numerical model is suitable to be applied to future evolutions of the setup and/or other configurations.

This article offers two case studies to illustrate the challenges in applying mainstream engineering educational training in a different culture and context while also offering some suggestions for more integrated and context-based educational approaches. The overall goal is not to dissuade energetic and well-meaning engineers looking to make a difference in the lives of communities around the world (although it is clear that in many cases, engineering solutions implemented at community levels have had mixed results) but rather to suggest that developing skills and contextual awareness to supplement those that they receive in traditional engineering programs is necessary to succeed in being part of a process of positive change in communities. This article will hopefully inspire engineering students and engineers to reflect on and ask important questions before they design solutions for communities different from the ones they grew up in. [ABSTRACT FROM AUTHOR]

The two-stage process for the treatment of rare earth phosphate minerals, involving an oxalic acid conversion leach and subsequent EDTA dissolution, has been demonstrated as a promising alternative to conventional extraction methods. To underpin a more detailed understanding, this work serves to further develop knowledge of the linkage between the stages and key practical aspects of the operation of the EDTA dissolution. A more detailed treatment of the phenomena observed in the EDTA treatment, characteristics of the solids, mass loss in dissolution, and the impact of parameter alterations in both stages provide greater holistic knowledge of the proposed flowsheet and considerations that will need to be addressed when increasing scale. Acid production (indicated by a pH decrease) in the EDTA dissolution stage was shown to be a feature of the reaction and not of residual acid associated with the solids from the oxalic acid stage. The consistency with which the rare earths were dissolved with respect to the phosphorus provided greater confidence that Nd and Pr (greater dissolution than P) are recovered at a higher efficiency than Ce and La (poorer dissolution than P). This was only not the case at high solids loading across both tests, leading to both oxalate and EDTA-deficient systems, respectively. Under high conversion conditions, it was demonstrated that Nd and Pr recoveries into solution approaching 70% were achieved. This equated to in excess of 17 gL−1 of total rare earths in solution. Solid/liquid separation was shown to be a significant challenge, created by both the fine particle size distribution of the leached residue and the dispersant nature of EDTA. [ABSTRACT FROM AUTHOR]

Global warming has significantly altered plant phenology by advancing the timing of leaf emergence, impacting vegetation productivity and adaptability. Winter and spring temperatures have commonly been used to explain spring phenology shifts, but we still lack a solid understanding of the effects of interactions between conditions in different seasons. This study utilizes normalized difference vegetation index (NDVI) and meteorological data to examine the effects of changes in winter and spring temperatures and precipitation on the start of the vegetation growing season (SOS) at high latitudes in China from 1982 to 2015. We found that SOS in Northeast China, as a whole, showed a weak advancing trend (moving earlier in the year), but with obvious regional differences. Even within the same vegetation type, changes in SOS were faster in the cold north (1.9 days/decade) and the cold and dry northwest (1.6 days/decade) than the regional averages for deciduous needleleaf forests (DNF; 1.2 days/decade) and grasslands (0.6 days/decade). Increases in spring temperatures dominate forest SOS advancement, while grassland SOS is mainly influenced by winter and spring precipitation. Decreases in winter minimum temperature (Tmin) enhance the spring temperature sensitivity of SOS. The way that winter precipitation regulates the spring temperature sensitivity of SOS differs among vegetation types: increasing sensitivity in grasslands but suppressing it in DNF. The moderating effects of winter conditions account for the greatest part of the regional differences in the magnitude of change in SOS. Our findings highlight that, although rising spring temperatures significantly affect SOS, winter Tmin and precipitation are crucial for understanding spatial SOS differences, particularly in cold, arid high-latitude regions. Winter conditions play an essential role in regulating the response of vegetation SOS to spring climate at high latitudes. These results suggest that considering the moderating effect of winter climate can facilitate more accurate predictions of temperature-driven phenological changes under future climate change. [ABSTRACT FROM AUTHOR]

Problem: Our nation faces an urgent need for more primary care (PC) physicians, yet interest in PC careers is dwindling. Students from underrepresented in medicine (UIM) backgrounds are more likely to choose PC and practice in underserved areas yet their representation has declined. Accelerated PC programs have the potential to address workforce needs, lower educational debt, and diversify the physician workforce to advance health equity. Approach: With support from Kaiser Permanente Northern California (KPNC) and the American Medical Association's Accelerating Change in Medical Education initiative, University of California School of Medicine (UC Davis) implemented the Accelerated Competency-based Education in Primary Care (ACE-PC) program – a six-year pathway from medical school to residency for students committed to health equity and careers in family medicine or PC-internal medicine. ACE-PC accepts 6–10 students per year using the same holistic admissions process as the 4-year MD program with an additional panel interview that includes affiliated residency program faculty from UC Davis and KPNC. The undergraduate curriculum features: PC continuity clinic with a single preceptor throughout medical school; a 9-month longitudinal integrated clerkship; supportive PC faculty and culture; markedly reduced student debt with full-tuition scholarships; weekly PC didactics; and clinical rotations in affiliated residency programs with the opportunity to match into specific ACE-PC residency tracks. Outcomes: Since 2014, 70 students have matriculated to ACE-PC, 71% from UIM groups, 64% are first-generation college students. Of the graduates, 48% have entered residency in family medicine and 52% in PC-internal medicine. In 2020, the first graduates entered the PC workforce; all are practicing in California, including 66% at federally qualified health centers, key providers of underserved care. [ABSTRACT FROM AUTHOR]

Training programs in pulmonary and critical care medicine have greatly expanded in the past decade, yet they do not reflect the racial/ethnic and economic diversity of the United States, which has significant implications for health equity. The lack of representation across medical education is likely to worsen with the recent Supreme Court decision banning affirmative action. The authors review health disparities in pulmonary and critical care medicine, the relationship of the workforce to health equity, and 10 tactics for addressing this urgent public health issue. [ABSTRACT FROM AUTHOR]